The shift toward minimally invasive surgical techniques presents a growing need for robotic or remotely controlled hand-operated surgical tools. These small-diameter surgical tools can be used to access a surgical site in a minimally invasive manner, while retaining the ability to allow the surgeon to manipulate the target tissue in order to perform a surgical procedure.
Currently, these procedures are implemented using small-diameter surgical tools, such as small diameter tubular probes, such as endoscopes, that are used to deliver a tool or end effector tailored to the specific procedure being performed. Since, however, these probes are rigid in construction, maneuvering the distal tip where the tool is located can become problematic. This is because small movements of the distally located tool can necessitate larger movement of more proximally located portions of the probe. These larger movements can be problematic because the anatomy simply will not permit the required movement of the probe, and because the probe can engage and potentially damage surrounding anatomical structures such as organs, vessels, nerves, muscles, bones, etc.
Accordingly, it is desirable to provide a system or apparatus that is capable of delivering surgical tools to a surgical target location and of permitting maneuvering of those tools without requiring that the entire delivery structure be manipulated as a whole. Most existing small diameter surgical tools do not include bendable or dexterous tips and thus cannot navigate the sharp corners encountered in surgery, such as those at the skull base, in the middle ear, and in the ankle. Moreover, dexterity driven tasks, such as tissue resection and suturing, can be difficult to perform without a bendable tip, especially through the small openings characteristic of natural orifice or percutaneous procedures.
Recent advances in surgical robotics are enabling less invasive access to the human body through natural orifices. Transoral surgery has been an approach of substantial recent interest, perhaps since the mouth is the largest natural orifice. Many in the surgical community have focused on using Intuitive Surgical, Inc.'s da Vinci™ Surgical System robot for this purpose, while engineering interest has focused on custom designed robot solutions. There has been a recent progression in the surgical robotics community toward designing robots to work through ever smaller orifices. Numerous systems have been designed for colorectal inspection and surgery. Recently, teleoperated and/or cooperative systems have been developed for ear surgery, endonasal surgery, and transurethral bladder surgery. Yet despite the relatively small diameter of the urethra, it is also interesting to note that transurethral surgery was actually one of the earliest surgical robotics applications.
Benign prostatic hyperplasia (BPH), or enlargement of the prostate, is the most prevalent symptomatic disease in men, occurring in 8% of men in their 30s, 50% in their 50s, and 90% in their 80s. BPH occurs when the prostate grows large enough that it restricts the flow of urine through the urethra, which passes through the prostate. The goal of a surgical intervention for BPH is to remove prostate tissue surrounding the urethra and thereby enable normal urine flow to resume. Transurethral resection of the prostate (TURP) is the current standard surgical approach for BPH. It is accomplished endoscopically, through the urethra, and prostate tissue is removed in pieces by either sharp dissection or electrocautery. Although the approach to the prostate is minimally invasive, the tools used to remove tissue can cause substantial bleeding (potentially requiring transfusion), long catheterization time, urethral narrowing, and bladder neck narrowing.
Holmium Laser Enucleation of the Prostate (HoLEP) is another surgical procedure for treating BPH. HoLEP can alleviate many of these concerns, since the Holmium laser provides an ideal combination of cutting and coagulation. HoLEP enables dissection without significant thermal spread (making HoLEP safer than electrocautery for nearby structures such as nerves), and without substantial blood loss. The reduction in morbidity in HoLEP compared to TURP has been corroborated in a number of clinical studies. These show that HoLEP reduces average catheterization time (2 days to 1 day), hospital stay (3 days to 2 days), and blood loss (eliminates the need for transfusions). The improvement in outcomes is sufficiently compelling that HoLEP is now generally viewed in the urology community as the superior treatment.
In spite of this, HoLEP adoption has been slow, and it is currently only conducted in relatively few institutions in the USA compared to TURP, which was conducted approximately 50,000 times in the United States in 2005. The best explanation for why HoLEP has not been more widely adopted is that it is extremely challenging for the surgeon. The challenge is brought about due to the fact that the laser proceeds straight out of the endoscope and can only be aimed by moving the entire endoscope. Since the endoscope must pass through a great deal of soft tissue on the way to the prostate, its maneuverability is limited. Large forces are required to aim the endoscope and the only way to physically manipulate tissue near its tip is to use the tip of the endoscope itself. It is challenging and physically demanding for surgeons to attempt to accurately aim the laser using the endoscope while simultaneously applying large forces to the same endoscope to deform the tissue.